The present invention relates generally to the field of biopsy devices and the methods of using such devices. More specifically, it relates to a device and method for accessing a targeted site of pathologically suspect tissue mass within a patient""s body, so as to facilitate the taking of a specimen of the tissue mass.
In diagnosing and treating certain medical conditions, such as potentially cancerous tumors, it is usually desirable to perform a biopsy, in which a specimen of the suspicious tissue is removed for pathological examination and analysis. In many instances, the suspicious tissue is located in a subcutaneous site, such as inside a human breast. To minimize surgical intrusion into the patient""s body, it is desirable to be able to insert a small instrument into the patient""s body to access the targeted site and then extract the biopsy specimen therefrom.
After removing the tissue specimens, additional procedures may be performed at the biopsy site. For example, it may be necessary to cauterize or otherwise treat the cavity which results from tissue specimen removal to stop bleeding and reduce the risk of infection or other complications. Also, it may be advantageous to mark the site for future surgical procedures should pathological tests performed on the biopsy specimen indicate surgical removal or other treatment of the suspected tissue mass from which the specimen was removed. Such marking can be performed, for example, by the apparatus and method disclosed and claimed in co-pending U.S. patent application Ser. No. 09/343,975, filed Jun. 30, 1999, entitled xe2x80x9cBiopsy Site Marker and Process and Apparatus for Applying It,xe2x80x9d which is hereby incorporated by reference in its entirety.
Electrosurgical techniques have been used in a variety of circumstances, including certain types of biopsy procedures. In electrosurgery, high frequency electrical energy is applied through an active electrode to patient tissue. The electrical energy flows through the tissue from the active electrode to a return electrode which is in contact with the patient""s tissue and which may be on the exterior of the patient""s body or intracorporeally disposed. Typically, the return electrode is attached to the patient at a point remote from where the primary or active electrode contacts the tissue. The tissue adjacent the primary electrode is ablated, to form an opening in the tissue. An electrosurgical biopsy instrument is disclosed and claimed in U.S. patent application Ser. No. 09/159,467 for xe2x80x9cElectrosurgical Biopsy Device and Method,xe2x80x9d assigned to the assignee of the subject application, and which is hereby incorporated by reference in its entirety.
This invention is directed to a biopsy device that provides ready access to a targeted tissue site within a patient""s body and provides for the separation and capture of a tissue specimen from the target tissue site. The biopsy device of the invention generally includes an elongated probe having a proximal end and a distal end and an inner lumen extending therein which is configured to be in fluid communication with a vacuum source. A small-dimensioned distal probe section is provided which has transverse dimensions less than adjacent probe portions distal to the small-dimensioned section, and which has one and preferably a plurality of apertures in a wall thereof in fluid communication with the probe""s inner lumen. A circular cutter is slidably disposed about the probe member and configured for rotation around, and translation along, the probe. Such longitudinal translation may be for a partial length, and preferably is for the entire length of the small-dimensioned distal probe section. The cutting surface of the circular cutter is disposed in a plane which is generally transverse and preferably perpendicular to the longitudinal axis of the probe.
The proximal end of the probe is configured to allow the inner lumen of the probe to be connected to a vacuum source, so that when a vacuum is applied to the inner lumen, tissue adjacent to the small-dimensioned distal probe section is pulled into contact with the distal probe section and thereby secures the tissue specimen to the distal probe section. With the tissue specimen secured to the distal probe section, the circular cutter may then be advanced distally, and preferably also rotated, to thereby separate the tissue specimen from the surrounding tissue bed to which the tissue specimen is secured and supported. The probe and the tissue specimen secured thereto may then be withdrawn from the patient.
In a preferred embodiment of the invention, the biopsy device has a thin, arcuate shaped distal electrode connected to the distal end of the probe and spaced distally therefrom as disclosed in copending application Ser. No. 09/477,255, filed on Jan. 4, 2000, and as disclosed in U.S. Pat. No. 6,331,166, both of which are incorporated by reference above. The distal arcuate electrode preferably lies in a plane that is parallel to and generally passes through a longitudinal axis of the elongated probe. The distal arcuate electrode preferably includes two or more electrode portions configured to flex or move in radial directions, such as within the plane parallel to the longitudinal axis. The maximal chordal dimension of the distal electrode is typically at least as large as the diameter of the distal end of the elongated probe, and is preferably greater than the diameter of the distal end of the probe to ensure that an opening made by the electrode is large enough to allow the biopsy device to be readily advanced through the tissue to the target site and through the suspicious tissue that will form at least part of the tissue specimen. Moreover, the distal electrode makes a planar cut through the desired specimen as it advances through tissue. Thus, when the circular cutter severs a specimen from supporting tissue as it advances over the small-dimensioned distal probe section, the specimen is typically formed circumferentially around the small-dimensioned distal probe section. Where the specimen includes the planar cut made by the distal electrode, the specimen may be split into two or more sections.
In a presently preferred embodiment, the biopsy device is provided with an access cannula, within which is disposed a supporting tube that is slidably disposed around and along a length of the probe. The supporting tube is disposed so as to cover at least part of the small-dimensioned distal probe section during advancement through tissue. The circular cutter is preferably disposed on the distal end of the supporting tube, and is configured to rotate within and to move longitudinally within the access cannula; the circular cutter is also configured to extend beyond the distal end of the access cannula, as it advances distally around the small-dimensioned distal probe. The access cannula may retract and advance as necessary to expose or cover portions of the circular cutter and supporting tube. In distal configurations, the access cannula, circular cutter and supporting tube may cover at least part of and preferably all of the small-dimensioned probe. When the access cannula, circular cutter and supporting tube are disposed in proximal configurations, at least a portion of the small-dimensioned probe may be exposed and configured to allow specimen tissue to be brought into contact with the small-dimensioned distal probe section. A vacuum may be applied to the inner lumen of the probe effective to pull tissue towards the small-dimensioned probe and to pull tissue into contact with the small-dimensioned probe where the specimen is secured. The circular cutter may be a separate member secured to or formed by the distal end of the supporting tube. Longitudinal translation of the circular cutter and supporting tube, preferably with rotation, is effective to separate a tissue specimen, or specimens, from the adjacent tissue. The supporting tube, with the circular cutter attached at its distal end, translates longitudinally at least partially within the access cannula, which serves to support and guide the supporting tube and cutter. The circular cutter and a distal portion of the supporting tube may extend distally from a distal end of the access cannula during distal translation and preferably rotation of the circular cutter. The access cannula also serves to shield and to protect body tissue from contact with a portion of the supporting tube as it translates and preferably also rotates during cutting operation.
Distal translation of the supporting tube over the small-dimensioned distal probe section effectively encloses and captures the severed tissue specimen(s) within the interior of the supporting tube.
After acquisition of a tissue sample, the biopsy device may be withdrawn from the patient, and once withdrawn, the specimen or specimen sections may be removed from the distal probe section for subsequent pathological examination. Alternatively, the probe, including the small-dimensioned distal probe section and the cutter attached to the supporting tube may be withdrawn, and samples recovered, while the access cannula remains in position at least partially within a patient""s body. The retention of the access cannula in place at least partially within a patient""s body aids in the recovery of subsequent samples, and aids in the delivery of markers, drugs, and the like to the location from which a tissue specimen was obtained.
The distal electrode is connected by means of an electrical conductor which extends to the proximal extremity of the probe, preferably through the inner lumen of the probe to a source of high frequency, e.g. radiofrequency (RF), electrical power.
The probe, including the distal radiofrequency cutter, proximal circular cutter and the supporting tube, and optionally the access cannula, are preferably configured for hand operation, or may be powered by a hand unit connected to a suitable controller. The probe, or components of the probe, including such components as the circular cutter and its attached supporting tube, the access cannula, and other components, are preferably configured to be sterilizable and to be disposable.
These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings.